Printing cylinder



y 1939- v m. E. NEIL SON 2,157,621

PRINTING CYLINDER Filed March 29, 1958 2 Sheets-Sheet l '/0 /c2 so 1220922303 R E. Nazis on,

Jbizzz May 9, 1939. J. P. E. NEILSON 2,157,621

PRINT ING CYLINDER Filed March 29, 1958 2 Sheets-Sheet 2 Izwezaua- @3222 1? E Nedsow,

Patented May 9, 1939 UNHTED STATES PATENT OFFICE PRINTING CYLINDER Application March 29, 1938, Serial No. 198,653

5 Claims.

This invention relates to printing cylinders and the object is to provide an improved construction for drawing and holding a flexible printing plate in close adherence about the periphery of the cylinder.

My invention will be well understood by reference to the following description of an illustrative embodiment thereof shown by way of example in the accompanying drawings, wherein:-

Figs. 1 and 2 are partial transverse sections of the cylinder illustrating respectively the plate about to be secured in position and the plate as finally secured;

Fig. 3 is a partial broken plan of the cylinder with the plate omitted; and

Fig. 4 is a fragmentary end elevation as seen from the left of Fig. 3.

Referring to the drawings, I have there shown a printing cylinder having a cylindrical platesupporting surface organized between the lateral bearers 6 and 8 (Fig. 3), and in Fig. 2 I illustrate the opposed ends l0 and E2 of a printing plate or of two separate printing plates clamped to the cylinder in opposed relation to secure the plate or plates to the cylindrical surface aforesaid. The construction which I am about to describe not only provides for easy application of the plate but for a powerful tensioning and firm clamping thereof in such a manner that there need be no gap or a very small gap between the opposed plate ends and the surface of the plate will be supported in the cylindrical surface so that its entire circumferential extent may be usefully availed of.

The cylinder is provided with a gap 54, herein defined by an overhanging edge Iii about which the inturned edge I!) of the plate is engaged, and an opposed crenellated edge defined by a series of projections or teeth 18, as best seen in Fig. 3, for reasons which will hereinafter appear. Herein this edge is shown as formed on a segmental piece 20 secured in a suitable recess in the main body of the cylinder by means of the bolts 22. Within the gap but adjacent the periphery of the cylinder there is provided a cylindrical supporting surface 2 3 which provides a bearing rotatably receiving a shaft 26 which is firmly supported by the bearing throughout substantially its entire length. Carried by the shaft is a bar 28 formed with a plurality of projections or teeth 39 corresponding in position to the crenels or spaces between the projections or merlons l8 of the crenellated edge and working in the spaces. The outer faces of these projections are formed cylindrically to the same radius as the cylinder proper and in the position of Fig, 2 coincident with this cylindrical surface. At the leading or left-hand end, referring to Figs. 1 and 2, of the cylindrical surfaces of the projections, they form hooks 32 adapted to enter and fit the 5 acute-angled hook formed by the inwardly and rearwardly bent edge l2 of the printing plate. Preferably the hooks 32 are formed by a slot 34 between the walls. of which the said bent-over plate end enters and is retained.

When the shaft 26 is rotated in its bearing 24 clockwise from the position of Fig. 2, the projections 18 are retracted within the crenels, opening a gap between the bar 28 and the overhanging edge [6 and moving the points of the hooks 32 to the right, viewing the figures, to permit the bent-over edge [2 of the plate to be engaged within the same. Because of the eccentric position of the shaft 26, when the bar is retracted in this manner the forwardly facing side of the hook corresponding to the upper wall of the slot 34 is disposed in the more nearly radial position of Fig. 1 as compared with Fig. 2, facilitating the insertion of the edge I2. When a slot is used, the bent-over edge of the plate is received between the walls thereof, and when the bar is moved back to the position of Fig. 2, tension is applied to the body of the plate without force tending to straighten out the bent-over edge l2. Also because of the eccentric position of the shaft 2 the end of the plate is drawn downwardly and inwardly toward or quite to abutting relation to the opposed plate edge In which is engaged over the overhanging edge 16 of the gap in the cylinder. In this position, as shown in Fig. 2, the portion 35 of the plate adjacent the bent-over edge I2 which spans the gap between the edge It and the uninterrupted body of the segment 2!] is efficiently supported throughout its circumferential extent by the projections I8 of the crenellated edge and the teeth or projections 30 of the bar which are disposed in overlapping staggered relation, as best seen in Fig. 3, and form continuations of the unbroken cylindrical surface of the rest of the cylinder.

Preferably the portion of the bar below the slot 34 is formed with a surface 36 which, when the bar is swung to the position of Fig. 2, cooperates with the overhanging surface of the unde'rcut edge IE to clamp thereagainst the inturned edge In of the sheet engaged thereover.

As best seen in Fig. 3, the shaft 26 may project beyond one of the bearers and have keyed thereto at the end of the cylinder an operating arm 38 in which (see Fig. 4) is tapped a screw 40 (omitted in Fig. 3) adapted to bear against an abutment 42 on the end wall of the cylinder. By means of this screw the shaft may be powerfully actuated from the position of Fig. 1 toward the position of Fig. 2, tensioning the plate and clamping it firmly in tensioned position.

I am aware that the invention may be em bodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:-

1. A cylinder having a gap, a cylindrical bearing inwardly of the gap, a shaft rotatably mounted in said bearing and receiving a substantially continuous support therefrom throughout its length, one edge of the gap being crenellated, and a bar carried by said shaft to engage the edge of a flexible sheet for application to said cylinder and having projections corresponding to the crenels and adapted to be retracted therein to provide a clearance in the gap, said bar having an outer face which, when the shaft is turned in a direction to carry the engaged edge of the sheet away from said edge, moves to a position lying in the surface of the cylinder.

2. A cylinder having a gap with a crenellated edge, a bar at the gap having an edge formed to fit into an acute angled hook formed by the inwardly turned edge of a sheet to be secured to the cylinder, means for swingingly mounting the bar eccentrically to the cylinder whereby, when turned to move the same into the throat of the hook, it will draw the sheet inwardly toward and. circumferentially about the cylinder, the bar having projections corresponding to the crenels and adapted to retract within the same when the bar is swung in opposite sense, the bar having an outer face which, when the bar is swung in a direction to carry the engaged edge of the sheet away from said edge, moves to a position lying in the surface of the cylinder.

3. A cylinder having a gap with a crenellated edge, a bar at the gap having a slot to receive the inwardly and rearwardly bent edge of a sheet to be secured about the cylinder, means for swingingly mounting the bar eccentrically to the cylinder, whereby when turned toward said edge the slot is presented at a more obtuse angle to the periphery of the cylinder, the bar having projections corresponding to the crenels and adapted to retract within the same when the bar is swung in opposite sense, the bar having an outer face which, when the bar is swung in a direction to carry the engaged edge of the sheet away from said edge, moves to a position lying in the surface of the cylinder.

4. A cylinder having a gap with a crenellated edge, a bar at the gap having a slot therein sloping inwardly and rearwardly toward said edge to receive between the walls of the slot the inwardly and rearwardly bent edge of a sheet to be secured about the cylinder, means for swingingly mounting the bar, the bar having projections corresponding to the crenels and adapted to retract within the same when the bar is swung in opposite sense, the bar having an outer face which, when the bar is swung in a direction to.

carry the engaged edge of the sheet away from. said edge, moves to a position lying in the surface of the cylinder.

5. A cylinder having a gap defined by an undercut edge and an opposed crenellated edge, a bar at the gap formed to fit into the hook formed by the inwardly and rearwardly bent edge of a sheet to be secured to the cylinder, means for swingingly mounting the bar, the back of the bar having projections corresponding to the crenels and adapted to be retracted therein to provide for facile engagement of the hook with the bar, said bar having an outer face which, when the bar is swung in a direction to carry the so engaged edge of the sheet away from said crenellated edge, moves to a position lying in the surface of the cylinder, and further having a portion which, when the bar is so swung, cooperates with the overhanging surface of said undercut edge to clamp thereagainst the inturned edge of. a sheet engaged thereover.

JOHN P. E. NEILSON. 

